Overvoltage stress events, including electrostatic discharge (ESD) events, electromagnetic impulse (EMI) events, electromagnetic pulse (EMP) events, and the like, can cause circuits to become damaged or malfunction. ESD events typically occur when a large voltage, often from build-up of static electricity, comes in contact with two terminals of a circuit. During manufacturing, human technicians can build up static charges. If a technician touches terminals of a circuit, for example if the technician is handling an integrated circuit part and touches external leads of the part, then the static charge can flow into the part and cause damage.
Many circuits include conduction path circuits that, in the case of an ESD event, direct and/or dissipate the ESD current so that damage does not occur to the part. Because of the high voltages associated with static charge buildup, these conduction path circuits often include high voltage or high power components that can withstand the power (and heat) dissipated by the ESD-related current. Using high voltage or high power components can be expensive in terms of part cost. If the circuit is an integrated circuit, the high voltage and power components may also require a relatively large semiconductor area.